Electrical box extension



FIG. 1 is a top-left-front perspective view of a first embodiment of an “electrical box extension” showing my new design;

FIG. 2 is a front elevational view thereof; the back elevational view is a mirror image thereof; and,

FIG. 3 is a left elevational view thereof; the right elevational view is a mirror image thereof. 

The ornamental design for an “electrical box extension,” as shown and described. 